I am using my MBL pretty much as it came out of the box. All I want to do is to add a second http site under a new port and read the data for that site from a different location than /var/www.

Creating the new site did work fine and as long as I create the data folder under /var/www everythings works fine. As soon as I try to set the root folder for my site to /shares/SOMESHARE it doesn't anymore. It turns out www-data doesn't have access to any folder inside of /shares/. Adding www-data to the group "share" didn't work, neither did it work when I chown/chgrp'ed the shares to www-data.